Cell Structure and Function

1. Cell Structure and Function

2. Learning Target I can discuss the history and components of the cell theory.

3. Cells • http://www.youtube.com/watch?v=RU5Ymc00S4w

4. Cells • A cell is the smallest living unit of life • Most are microscopic

5. Discovery of Cells • Robert Hooke from England (1665) • Observed sliver of cork • Saw “row of empty boxes” • Coined the term cell because it reminded him of monk’s cells

6. Discovery of Cells • Anton van Leeuwenhoek • From Holland • Observed tiny moving organisms in pond water • Animalcules

7. Cell theory • (1838)Theodor Schwann, German biologist • (1839) Matthias Schleiden, German botanist “ all living things are made of cells” • (1855) Rudolf Virchow “all cells come from pre-existing cells”

8. Principles of Cell Theory • All living things are made of cells • Cells are the basic units of structure and function in living things. • New cells are produced from existing cells.

9. Cell Size

10. Cells Have Large Surface Area-to-Volume Ratio

11. Characteristics of All Cells • Cell (Plasma) membrane -- A surrounding protective membrane • Cytoplasm – cell contents in thick fluid • Control center with DNA

12. Learning Target I can discuss the history and components of the cell theory.

13. Learning Target I can analyze the similarities and differences between prokaryotic and eukaryotic cells.

14. Cell Types • Prokaryotic • Eukaryotic

15. Review • What are the characteristics of life?

16. Prokaryotic Cells • First cell type on earth • Small with simple structure • Possess all characteristics of life • Cell type of Bacteria and Archaea

17. Prokaryotic Cells • No membrane bound nucleus • Nucleoid = region of genetic material (DNA) • Organelles not bound by membranes

18. Eukaryotic Cells • Nucleus bound by membrane; contains genetic material (DNA) • Include fungi, protists, plant, and animal cells • Possess many organelles Protozoan

19. Learning Target • I can analyze the similarities and differences between prokaryotic and eukaryotic cells.

20. Learning Target • I can describe the functions of all major cell organelles.

21. Composite Animal Cell

22. Composite Plant Cell

23. Cell Structure • Eukaryotic cell is divided into two major parts: • Nucleus • Cytoplasm • the portion of the cell outside the nucleus; organelles are suspended in this

24. Nucleus • Control center of the cell • Found in plant and animal cells • Surrounded by a double membrane • Contains nearly all cell’s DNA • Chromatin

25. Nuclear Envelope • Separates nucleus from rest of cell • Double membrane • Has nuclear pores to allow movement of materials into and out of the nucleus

26. DNA • Hereditary material stored in the nucleus • Chromosomes contain the DNA which contain the instructions for controlling the cell’s functions • Most of the time the DNA is coiled into chromatin • Chromosomes are seen as coiled strands inside the nucleus is the genetic material seen in the nucleus

27. Nucleolus • Found inside the nucleus • Most cells have 2 or more • Directs synthesis of RNA • Produces ribosomes

28. Ribosomes • Small particles of RNA and protein • Located all over the cell • Site of protein synthesis • Assembles amino acids into proteins • Can be free or attached

29. Endoplasmic Reticulum • Helps move substances within cells • Network of interconnected membranes • Two types • Rough endoplasmic reticulum • Smooth endoplasmic reticulum

30. Rough Endoplasmic Reticulum • Has ribosomes attached to surface • Manufacture proteins • Not all ribosomes are attached to rough ER. Some are free in the cytoplasm • May chemically modify proteins from ribosomes

31. Smooth Endoplasmic Reticulum • No attached ribosomes • Has enzymes that help build molecules • Carbohydrates • Lipids

32. Golgi Apparatus • Involved in synthesis of plant cell wall • Modifies, sorts and packages proteins and other materials from the ER for storage in the cell or for secretion outside of the cell.

33. Golgi Apparatus Function 1. Molecules come in vesicles 2. Vesicles fuse with Golgi membrane 3. Molecules may be modified by Golgi 4. Molecules pinched-off in separate vesicle 5. Vesicle leaves Golgi apparatus 6. Vesicles may combine with plasma membrane to secrete contents

35. Lysosomes • Contain digestive enzymes • Functions • Aid in cell renewal • Use enzymes to break down food and worn out cell parts • Digests invaders

36. Vacuoles • Membrane bound storage sacs • More common in plants than animals • Store • Water • Food • Wastes

37. Mitochondria • Have their own DNA • Bound by double membrane

38. Mitochondria • Produces the energy a cell needs to carry out its functions • Break down fuel molecules (cellular respiration) • Glucose • Fatty acids • Release energy • ATP

39. Chloroplasts • Capture energy from the sun and convert it into chemical energy • Photosynthesis

40. Microfilaments/Microtubules • Located all over the cell • 3 functions: • mechanical support • anchor organelles • help move substances

41. A = actin, IF = intermediate filament, MT = microtubule

42. Cilia & Flagella • Provide motility • Cilia • Short • Used to move substances outside human cells • Flagella • Whip-like extensions • Found on sperm cells

43. Cilia & Flagella Structure • Bundles of microtubules • Continuous with plasma membrane

44. Centrioles • Pairs of microtubular structures • Play a role in cell division

45. Learning Target • I can describe the functions of all major cell organelles.

46. Learning Target • I can explain how the cell membrane controls movement of substances both into and out of the cell and within the cell.

47. Cell Membrane • Also known as the plasma membrane • Contains cell contents • Double layer of phospholipids & proteins • Controls what enters or exits the cell

48. Phospholipids • Polar • Hydrophilic head • Hydrophobic tail • Interacts with water

49. Cell Walls • Found in plants, fungi, & many protists • Surrounds plasma membrane; provides support and protection for the cell

50. Cell Wall Differences • Plants – mostly cellulose • Fungi – contain chitin